there isnt any quick fix method to remembering how to identify...
my suggestion is that u first remember the solubility rules roughly. This itself can help you in many situations to determine what cations and anions are present in a solution..
then once you know that, check out conquering chemistry (dont get too bogged down in the details though) or even csu online website for 'flowcharts' on determining what chemical species are present in a given solution.